Getting up close and personal with a furry tarantula is probably the very last thing someone with a spider phobia would opt for, but the encounter may be the ticket to busting the brain's resistance to arachnids.
A tried-and-true exposure therapy, this one lasting just hours, changed activity in the brain's fear regions just minutes after the session was complete, researchers found.
"Before treatment, some of these participants wouldn't walk on grass for fear of spiders or would stay out of their home or dorm room for days if they thought a spider was present," said lead study author Katherina Hauner, postdoctoral fellow in neurology at Northwestern University Feinberg School of Medicine, in a statement.
After a single therapy session lasting up to three hours, "they were able to walk right up and touch or hold a tarantula. And they could still touch it after six months," Hauner said.
Spider phobia is a type of anxiety disorder called specific phobia, which also includes phobias of blood, needles, snakes, enclosed places and others. About 9.4 percent of the U.S. population has experienced a specific phobia at some point in their lifetime, Hauner said.
Hauner told LiveScience she hopes people who have specific phobias, particularly of spiders, will realize that successful treatments are out there, and that their phobias can take just hours to cure (though some cases can take a couple weeks to cure, she noted). "It's still not easy. It involves being motivated to overcome your fear."
Hauner and her colleagues examined 12 adults, nine women and three men with an average age of 22, who met diagnostic criteria for having a spider phobia; their arachnid fear was so great that, before therapy, they had trouble even looking at photos of spiders. And when they did get a glimpse, each phobic's brain showed increased activity in regions linked to fear response, including the amygdala, insula and cingulated cortex, in functional magnetic resonance imaging (fMRI) scans.
When asked to touch a tarantula in a closed terrarium, participants were also too afraid to go no closer than an average of 10 feet away. [In Photos: Tarantulas Strut Their Stuff]
"They thought the tarantula might be capable of jumping out of the cage and on to them," Hauner said. "Some thought the tarantula was capable of planning something evil to purposefully hurt them."
In therapy, the participants learned about tarantulas in general and that their oversized fears of the creepy crawlies were just that. They were also guided through a multistep process that inched them closer to the enclosed tarantula until they could actually pick up and hold the spider. (At one point they touched the tarantula with a paintbrush, next while wearing a glove and eventually they pet it with their bare hands or held it.)
"I would teach them the tarantula is fragile and more interested in trying to hide herself," Hauner said.
Fearful brain changes
Minutes after therapy, participants were again shown spider photos, but this time, their fMRI scans showed less activity in the fear regions. This fear reduction persisted for six months after treatment, the researchers said.
At that six-month mark, participants were asked again to touch the terrarium-enclosed tarantula. "They walked right up to it and touched it," Hauner said. "It was amazing to see because I remembered how terrified they were initially and so much time had passed since the therapy." [What Scares You? (Infographic)]
The brain area linked to inhibiting emotions or fear, called the prefrontal cortex, showed lots of activity minutes after therapy. However, six months later, that brain area became significantly less active when participants viewed spider photos. "They were still not afraid of spiders, but this particular region of the brain reacted differently," Haunter said during a telephone interview.
The researchers could also predict which participants would gain the most from therapy by looking at the extrastriate cortex, a brain region linked to visual perception and how the brain interprets images. The higher the activity in that area minutes after therapy, the best behavioral progress was seen six months later.
While a lot of people may be at least a little afraid of spiders, to meet the criteria for a specific spider phobia, Hauner says that fear must interfere with your life. For instance, those with a spider phobia may leave a dorm room or other living area for days after spotting a spider there; or they might avoid outdoor activities for fear of contact with a spider.
The results are detailed this week in the journal Proceedings of the National Academy of Sciences.